Plateosaurus

Many skeletons of Plateosaurus-which is the best known of the prosauropods-have been found in the south of Germany, as well as in France and Switzerland. A harmless plant-eater with numerous small, pointy teeth, all of uniform size and shape, Plateosaurus roamed in herds around the northern part of Laurasia during the late Triassic. It was one of the first of the large dinosaurs.

Plateosaurus had stout limbs that supported the considerable weight of the animal as it walked on all four legs. As with other prosauropods, Plateosaurus's hind legs were stronger than the front ones and were able to take the weight of the creature when it reared up, either to reach higher branches for food, or possibly to defend itself against attack-a particularly large claw on each thumb would have been an effective weapon in such a circumstance. Its long tail would have acted as a counterbalance to the long, thick neck.

Small ridges of bone around Plateosaurus's mouth supported cheek pouches that could have held a mouthful of leaves while the front teeth went on stripping more leaves from a tree branch. The cheeks also served to prevent food from falling out of the mouth while the animal chewed, breaking the plant matter down into a mush that it could then swallow.

In at least one instance-near the German town of Trossingen-a herd of Plateosaurus appear to have been killed in a flash flood. The floodwaters buried the skeletons together in a jumbled mass. From this remarkable deposit paleontologists have been able to reconstruct what a herd of Plateosaurus probably looked like. It would have included animals of different ages-from very young to very old-that found safety in numbers as they moved about in search of food.

Paleontologists once thought that prosauropods such as Plateosaurus were the ancesters to those later giants of the jurassic, the sauropods. Now, however, they are recognized as a separate group in their own right.